Question

larger and tend to be clustered near the will appear as small densely stained spots. Archegonia are Notebook Assignment 5 a. Illustrate the prothallus labeling the rhizoids, antheridia, and archegonia. b. How many sets of chromosomes are contained of cells of these gametophyte structures: rhizoids, antheridia, archegonia, egg cells, sperm cells? c. Which cellular division results in the production of eggs and sperm cells, mitosis or meiosis? Why? d) In what important ways does the fern gametophyte differ from the sporophyte? How might this reflect the function of these two life-cycle stages.

Answer 1

In ferns, the gametophyte stage includes the haploid structures such as rhizoids, antheridia, and archegonia, with rhizoids anchoring the plant, and antheridia and archegonia producing sperm and egg cells respectively through mitosis. The fern gametophyte stage differs from the sporophyte stage in size, sexual reproduction function, and the absence of a vascular system, reflecting the life-cycle stages' distinct functions.

Step-by-step explanation:

The student's notebook assignment appears to be focused on the structure and genetics of fern gametophytes and how they differ from sporophytes.

The fern gametophyte

The prothallus is the gametophyte stage of ferns and includes structures such as rhizoids, antheridia, and archegonia. The rhizoids act like roots anchoring the prothallus to the substrate. The antheridia are structures where sperm cells are produced, whereas archegonia are flask-shaped structures containing a single egg cell.

Chromosome sets in gametophyte structures

All these structures, including the egg and sperm cells, are haploid and contain one set of chromosomes as they are part of the gametophyte, which is the haploid stage of the fern's life cycle.

Cell division and gamete production

Eggs and sperm cells in ferns are produced by mitosis, not meiosis, because the cells of the gametophyte from which they originate are already haploid.

Differences between gametophytes and sporophytes

The fern gametophyte is a small, heart-shaped autotrophic plant that reproduces sexually and is anchored to the ground by rhizoids. In contrast, the fern sporophyte is what we typically recognize as a fern – with fronds and a vascular system – and reproduces asexually by producing spores. The sporophyte stage is dominant in the fern life cycle, and its structural adaptations are more geared towards efficient spore dispersal rather than sexual reproduction, as seen in the gametophyte stage.